Blueberry plant denominated ‘Liberty’

ABSTRACT

Liberty is a new blueberry variety of  Vaccinium corymbosum.  It is a productive, very late ripening variety with high fresh market quality intended for areas where northern highbush varieties are grown successfully. Plants of Liberty are vigorous and upright. Canes are numerous, moderately branched and the fruit are well exposed. Its berries are moderately large, have small, dry picking scars, excellent powder-blue color, delicious flavor and excellent firmness. Liberty has a harvest season that begins about 5 days before the variety known as ‘Elliott’.

Latin name and variety denomination:

The present invention relates to a new and distinct variety of Vaccinium corymbosum, which is hereby denominated ‘Liberty.’

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to the present inventor's United States Patent Applications entitled “Blueberry plant denominated ‘Aurora,’” U.S. patent application Ser. No. 10/350,345, filed Jan. 23, 2003, and entitled “Blueberry plant denominated ‘Draper,’” U.S. patent application Ser. No. 10/350,344, filed Jan. 23, 2003. Both of these applications are also assigned to the assignee of the present application. The disclosures of the above applications are hereby incorporated herein by reference.

SUMMARY OF THE INVENTION

The present invention relates to a new and distinct variety of highbush blueberry plant, denominated ‘Liberty.’ Liberty is a new blueberry variety of Vaccinium corymbosum from the Michigan State University breeding program. It is a productive, very late ripening variety with high fresh market quality that is intended for areas where northern highbush varieties are grown successfully. Plants of Liberty are vigorous and upright. Canes are numerous, moderately branched and the fruit are well exposed. Its berries are moderately large, have small, dry picking scars, excellent powder-blue color, delicious flavor and excellent firmness. Liberty has a harvest season that begins about 5 days before the variety known as ‘Elliott.’ Blueberry growers often receive their highest profits in the late season. Liberty will provide two new late ripening options with high quality fruit.

Emasculated flowers of the ‘Brigetta’ highbush blueberry from Australia were pollinated in 1991 with pollen from the northern highbush variety Elliott. The seeds were germinated, grown in a greenhouse for 1 year and then field planted at Benton Harbor, Mich. Liberty was selected from a group of 54 siblings in 1997. The original selection has been evaluated at Benton Harbor, Mich. annually for 11 years. Asexual reproduction took place at East Lansing, Mich. and Lowell, Oreg. Liberty has been propagated by hardwood cuttings that produced over a hundred shoots that were rooted in the greenhouse and then planted in the field. Initiation of root development from hardwood cuttings takes about two to about three months. In addition, Liberty has been propagated by softwood cuttings that have been rooted. Furthermore, generation of micro-shoots in the greenhouse using established tissue culture methods has produced thousands of clones of Liberty. Initiation of root development from hardwood cuttings takes about three to about four weeks. Such methods are discussed in the following references, which are incorporated by reference in their entirety: Doran, W. L. and Bailey, J. S. “Propagation of the high bush blueberry by softwood cuttings,” Bulletin Massachusetts Agricultural Experiment Station; no. 410. Amherst, Mass. Massachusetts State College, 1943; Doehlert, C. A. “Propagating blueberries from hardwood cuttings,” Circular (New Jersey Agricultural Experiment Station) 490. New Brunswick, N.J. New Jersey Agricultural Experiment Station, 1945; Doehlert, C. A. “Propagating blueberries from hardwood cuttings,” Circular (New Jersey Agricultural Experiment Station) 551. New Brunswick, N.J.: New Jersey Agricultural Experiment Station, 1953; El Shiekh, A.; Wildung, D. K.; Luby, J. J.; Sargent, K. L.; Read, P. E. “Long term effects of propagation by tissue culture or softwood single node cuttings on growth habit, yield, and berry weight of ‘Northblue’ blueberry,” Journal of the American Society for Horticultural Science. 1996, 121: 2, 339 342; Galletta, G. J.; Ballington, J. R.; Daubeny, H. A.; Brennan, R. M.; Reisch, B. J.; Pratt, C.; Ferguson, A. R.; Seal, A. G.; McNeilage, M. A.; Fraser, L. G.; Harvey, C. F.; Beatson, R. A.; Hancock, J. F.; Scott, D. H.; Lawrence, F. J.; Janick, J. (ed.); Moore, J. N. “Fruit breeding. Volume II. Vine and small fruits,” Department of Horticulture, Purdue University, West Lafayette, Ind. 1996 John Wiley and Sons; New York; USA; Strik, B.; Brun, C.; Ahmedullah, M.; Antonelli, A.; Askham, L.; Barney, D.; Bristow, P.; Fisher, G.; Hart, J.; Havens, D. Draper A. D. and Chandler C. K. “Accelerating highbush blueberry selection evaluation by early propagation,” Journal of the American Society for Horticultural Science. 1986 111(2): 301-303; Pritts M. P. and Hancock J. F. (Eds.) “Highbush blueberry production guide,” Northeast Regional Agricultural Engineering Service, Ithaca, N.Y., USA 1992.

Clones of Liberty have been tested for four years at Grand Junction, Mich., and for two years at South Haven, Mich., Lacota, Mich., Corvallis, Oreg., and Lowell, Oreg. In all cases all resulting plants have stably displayed characteristics of the variety. Consistent high yields at Benton Harbor and Grand Junction, Mich. indicate that the buds and wood of Liberty are tolerant to fluctuating late fall and spring temperatures. Liberty also has excellent winter hardiness, as it has routinely been challenged with mid-winter temperatures below −20 C. Probable areas of adaptation and markets include blueberry growers in Michigan and across the USA, Canada, Argentina, Australia, Chile, France, Germany, and New Zealand.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 is a photographic print in full color of exemplary 4-year-old Liberty blueberry plants. Two plants are shown, one in the left foreground and a portion of a second plant in the right foreground. The plants appearing in the background are of a different variety and are not part of the Aurora blueberry plants, nor is the grass appearing in the picture part of the Aurora blueberry plants.

FIG. 2 is a photographic print in full color illustrating exemplary fruit clusters of a 4-year-old Liberty blueberry plant. Some of the fruit is not yet mature and does not show the characteristic mature color.

DETAILED BOTANICAL DESCRIPTION

The following a is detailed botanical description of the new and distinct variety of blueberry, its flowers, fruit and foliage, based on observations of specimens grown at Benton Harbor, Mich. and Grand Junction, Mich. over four years, and at South Haven, Mich., Lacota, Mich., Corvallis, Oreg., and Lowell, Oreg., over a two year period. The taxonomic characteristics chosen in the detailed description are standard in the practice (R E Gough, R J Hindle, and V G Shutak, “Identification of Ten Highbush Blueberry Cultivars using Morphological Characteristics,” HortScience 11 (5): 512-4, 1976). Color descriptions, except those given in common terms, are presented in Royal Horticultural Society Colour Chart designations. In cases where the color descriptions cited from The Royal Horticultural Society Colour Chart differ from the colors shown in the drawings, the colors cited from The Royal Horticultural Society Colour Chart should be considered accurate. Any deviation from these colors in the drawings is due to failure of the photographic process to exactly duplicate the colors of nature. In addition, fruit color designations in Table I are applicable only to mature fruit.

Liberty requires pollination for fruit development; it is self-fertile but pollen from any highbush blueberry species will initiate fruit development.

TABLE I Liberty Characteristics Characteristic Liberty Bush Mature height 1.5 m Mature width 1.2 m Diameter/width ratio 1.4 Growth habit Upright to semi-spreading Annual renewal canes 5-6 Internode length on 2.5 cm spring shoots Mature cane color Greyed-Green (198A) Mature cane length 1.5 m Mature can width 2 cm-4 cm Fall color-new shoots Patches of Red-Purple (60A) Foliage Leaf shape Elliptic-ovate Apex shape Acute Base shape Cuniate to Truncate Leaf length 3.0 cm-4.5 cm Leaf width 1.4 cm-2.4 cm Leaf length/width ratio 2.1 Leaf serration Serrated Pubescence None Color-top Green (137A) Color-bottom Green (138A) Veination Palmate Vein color Green (138B) Petiole length 4 mm Petiole color Green (138B) Blossoms Shape of corolla Elongate-urceolata Calyx 5 lobed Style length At edge of corolla Color of open flower Mostly white (155D) Flower # per cluster 8-10 Flower diameter 5 mm-7 mm Reproductive Organs Type Berries with seeds Seed Size 1 mm × 2 mm Number of seeds 10-50 per fruit Mature Fruit Shape Globose, uniform Length 1.1 cm-1.3 cm Width 1.4 cm-1.8 cm Color 156D Color with bloom Violet Blue (98A) Color without bloom Blue (103A) Pedicel scar size 1.44 mm Pedicel length 2 mm-3 mm Pedicel color Green (143B) Average weight 1.5 gm

In trials in Michigan and Oregon, Liberty has consistently had better color, was firmer and had a better picking scar than Elliott (Tables II and III). They also had greatly improved flavor. In several post-harvest trials, the relative fruit rot susceptibility of the Elliott and Liberty genotypes was similar and good (Table IV). Liberty proved to have a dramatically longer storage life than Elliott in 2000 and a slightly longer one in 2001. It is not known why Liberty stored so much better in 2000 than 2001 and 2002, except that temperatures during the harvest period were exceptionally hot in the latter two years. The fruit are eaten fresh, frozen or processed into products like jams, jellies and yogurt.

Liberty is distinguishable from Aurora (co-pending application Ser. No. 10/350,345, filed Jan. 23, 2003) in that Liberty is first harvested about 10-14 days before Aurora (mid-August vs. late August to early September in Michigan). Liberty leaves are serrated, while Aurora leaves are entire. The bush height/width ratio of Liberty is about 1.4, while Aurora's is about 1.1.

Liberty is distinguishable from Draper (co-pending application Ser. No. 10/350,344, filed Jan. 23, 2003) in that Liberty is harvested 6-7 weeks after Draper (mid-August vs. late June-early July in Michigan) Liberty has a bush height/ratio of about 1.4, while Draper's is about 2.2. Liberty's leaves are elliptic-ovate (leaf/length ratio is >2), while Draper leaves are narrow elliptic (leaf/length ratio is <2) Liberty leaves are serrated, while Draper leaves are entire.

TABLE II Characteristics of mature ‘Liberty’ in comparison to ‘Elliott’ at Benton Harbor, MI in 2001 and 2002. All values were the same in both years, except for harvest date. The rating scale was 1-9, with 1-4 = inferior, 5-6 = acceptable, 7 = good, 8 = very good and 9 = superior. Traits Liberty Elliott Horticultural Date of first harvest 8/18 and 8/22 8/23 and 8/27 Fruit load 7 8 Size 7 6 Color 8 6 Picking scar 8 7 Firmness 8 7 Flavor 8 5 Taxonomy Leaf margin serrated entire Leaf shape elliptic- elliptic ovate Leaf length/width ratio >2 <2 Bush diameter/width 1.4 1.4 ratio Fall color on 1-year red and solid red shoots green Bark texture-mature rough and rough wood flacky

TABLE III Mean fruit ratings of ‘Liberty’ and ‘Elliott’ at Grand Junction, MI, Corvallis, OR and Lowell, OR in 2002. Plants were set as two-year-old rooted cuttings in 2000. Evaluations were made when the bushes were 50% ripe. Fruit Picking Location Cultivar load Size Color scar Firmness Flavor Grand Liberty 7^(z) 7 8 8 8 8 Junction Elliott 8 6 6 7 7 5 Corvallis Liberty 8 7 8 8 8 8 Elliott 9 6 7 7 7 6 Lowell Liberty 8 7 8 8 8 8 Elliott 9 6 7 7 7 6 ^(z)The rating scale 1-9, with 1-4 = inferior, 5-6 = acceptable, 7 = good, 8 = very good and 9 = superior.

TABLE IV Postharvest storage life and fungal rots of ‘Elliott’ and ‘Liberty’ harvested at Benton Harbor, MI. Fruit were picked on the same day, when the bushes were 30-40% ripe. Determinations Liberty Elliott Percentage of fruit rotted^(X) 2000  4% 12% 2001 16% 12% 2002 11% 10% Types of fruit rots in 2002^(Y) Alternaria  6 6 Colletotrichum  2 4 Botrytis  2 0 Storage life (days)^(Z) 2000 35 7 2001 14 7 2002  7 7 ^(X)Four pints of fruit were evaluated after being held tor 3 weeks at 2 C in zip-lock storage bags. Fungal species were not determined. ^(Y)Fifty fruit were randomly selected from 4 pints and held for ten days at room temperature. ^(Z)Four pints of fruit were held at 2 C in plastic zip-lock bags and examined at 7 day intervals. The containers were considered non-salable, if more than a few fruit appeared rotten or >25% were soft to the touch.

Elliott and Liberty have high contents of phenolics and antioxidants relative to other blueberry varieties. A comparison of phenolics and antioxidants of various blueberry varieties is provided in Table V.

TABLE V Mean values for antioxidant activity, total phenolic content and anthocyanin content of fully ripe, fresh blueberries (Source - Conner, A. M., J. J. Luby, J. F. Hancock, S. Berkheimer and E. J. Hanson. 2002. J. Agric. Food Chem. 50: 893-898. Antioxidant Phenolic Anthocyani Cultivar activity^(x) content^(y) n content^(z) Bluecrop 11.1 402 123 Bluegold 13.1 492 181 Brigetta 9.0 335 132 Elliott 14.3 515 191 Jersey 7.8 336 121 Legacy 12.2 470 143 Liberty 14.2 494 202 Nelson 9.0 376 93 Tukey's HSD 3.7 118 52 ^(x)μmol TE g⁻¹ fresh fruit ^(y)mg chlorogenic acid equivalents/100 g fresh fruit ^(z)mg cyanidin 3-glucoside equivalents/100 g fresh fruit 

What is claimed is:
 1. A new and distinct highbush blueberry plant, substantially as illustrated and described herein. 